Dogs and cats fed quality commercial diets rarely need any extra calcium supplements.
The main message is DO NOT OVERDOSE
Giving extra calcium/D3 as a routine to pregnant bitches is controversial. There is the strongly held view that calcium is necessary for healthy foetal development and that it may prevent the onset of eclampsia after birth. But, there is also a strongly held view that it isn't necessary as a routine AS LONG AS THE BITCH IS CONSUMING A WELL-BALANCED, HIGH QUALITY COMMERCIAL FOOD. The higher needs of the bitch (and queen) are met by her eating more. Usually 1.25-1.5 times normal, fed as several small meals throughout the day.
The problems occur with specific breeds or individuals where a large litter may reduce food intake simply by virtue of the room occupied by the puppies or kittens in the abdomen. Some individuals simply won't eat more, and some simply have an inbuilt 'issue'.
Some experts claim that supplementing without 'need' may cause soft-tissue calcification or deformities. There is even some evidence that supplementing with calcium at this time when there isn't a 'need' can increase the likelihood of eclampsia /tetany by depressing normal regulatory mechanisms.
However, calcium supplementation following veterinary advice is different. This will be given for specific reasons. Often because a bitch isn't eating sufficient amounts of a quality commercial diet for whatever reason.
Normal Calcium levels in a diet are usually between 0.5-1% dry matter, the higher level is needed for growth, dropping to the lower for maintenance. Pregnant and lactating bitches may need up to 1.4%. Calcium absorption in many animals including dogs is of two types, one requires vitamin D3 to move the calcium into the blood supply, the other mechanism which is dominant in young animals but which fades as they age is simple absorption depending on the level of calcium in the gut. Serious problems have been caused by oversupplementing calcium in puppies etc.
Requirements for supplementing D3 are also controversial and conflicting! Studies showed that dogs fed 'practical' diets and exposed to adequate sunlight do not require extra D3 (in the 2 years of the study). BUT, other data indicates that dogs and cats simply don't produce enough D3 using sunlight (even if given UV lamps!). For this reason it is included in commercial diets. It is very easy to overdose and cause problems.
Veterinary advice recommends around 25-50mg elemental calcium/kg/day to be given to bitches which have suffered eclampsia, for the remaining part of their lactation. The easiest source is Calci-Dust (calcium carbonate) on food, if the water route is preferred then calcium lactate is suitable, and finally if vitamin D3 is required as well then 0.03-0.06 µg/kg/day is recommended.
129.8 mg Ca / g, = approx 425mg/scoop - enough for 12 kg of dog if put in a days water, or 6kg if in two days water.
400mg Ca / g or roughly 35-40mg per pinch - so again ROUGHLY 1 pinch per kg of animal = 1300 mg /scoop - enough for 35 kg of dog/day
35mg Ca /ml AND 25 IU of vitamin D3, so 1ml provides enough D3 for 12kg
FOR A STANDARD 12kg DOG
One scoop of Calcium lactate per day in its daily drinking water
One third scoop of Calci-Dust per day spread through food
AND, IF D3 is required as well
1ml of Zolcal D. - this will also provide 35mg Ca (enough for a spare kg of dog - but since this is all approximated not enough to change the recommendation)
These figures are for guidance only, please consult your vet. We cannot take responsibility for use, all cases are different and many bitches/queens will require their blood calcium levels monitoring by blood test once or twice a week if they have a history of problems.
When comparing calcium sources it is important to calculate the dosage of calcium based on elemental (available) calcium, because different products vary in the amount of calcium available.